Drainage systems for removing body fluids by suction, for example for thorax drainage, for liposuction, for aspiration of blood or secretions during operations and for wound drainage, are known.
For this purpose, for example, a catheter is guided into a body cavity or a suction head is guided onto a wound. The catheter or the suction head is connected to a suction conduit that leads into a secretion collection container. A central vacuum system or a suction pump is used to generate an underpressure (relative negative pressure) in the suction conduit, such that the body fluid is sucked through the suction conduit into the collection container. In addition to the suction conduit, it is also known to use a service conduit which, for example, permits evacuation of air from the suction conduit.
Thus, WO 94/20152 discloses a drainage device for removing fluids by suction from a body cavity, in particular the pleural cavity. The device has a drainage conduit for removing the fluids by suction, and a vacuum pump for generating an underpressure in the body cavity. A gas can be introduced into the body cavity via an auxiliary conduit. This auxiliary conduit, at the end directed towards the patient, is in fluidic communication with the drainage conduit. Auxiliary conduit and drainage conduit are preferably arranged in a double-lumen tube. A pressure gauge is arranged at the end of the auxiliary conduit directed away from the patient, and it is proposed that the pressure difference between the flows in the auxiliary conduit and drainage conduit be determined.
U.S. Pat. No. 3,851,650 discloses a drainage tube with a connector piece for connection to a catheter. The drainage tube has a double-lumen design with a drainage conduit for removal of body fluid from a patient by suction and an auxiliary conduit for supply of air. To ensure that the body fluid removed by suction does not pass into the auxiliary conduit, a valve which is capable of opening the drainage conduit in one direction and sealing it in an opposite direction is arranged at the end of the auxiliary conduit directed towards the patient.
EP 0 599 472 likewise discloses the use of a double-lumen tube in a medico-surgical suction system.
These tubes require coupling units, for example in order to connect them to the suction catheter or to a suction head for a wound dressing or in order to increase the total length of the drainage tube. To ensure that no bodily secretions escape during release of the coupling unit, the drainage tube is usually first of all closed by a clamp. However, this makes handling more difficult and takes up more time when changing the drainage device. It is also sometimes forgotten to close the clamp. Moreover, at the time of reconnection, it is sometimes forgotten to open the clamp again, with the result that the drainage is not continued. Even when a monitoring system is present, it still takes some time before an error is reported. In addition, the coupling unit must not impede the supply of air to the suction conduit by way of an auxiliary conduit and/or a pressure measurement in the suction conduit.
In other fields at least, coupling units are known which have integrated valves and which thus prevent dripping from an uncoupled tube.
Thus, WO 2007/014281 and EP 1 840 443 describe coupling units for leaktight connection of two tubes, with a valve being arranged in each part of the coupling unit.
U.S. Pat. No. 4,541,457 discloses a coupling unit for a CO2 conduit. The unit comprises a male coupling part and a female coupling part. A valve which allows or prevents a flow stream in two opposite directions is arranged in the female coupling part, while a nonreturn valve is arranged in the male coupling part.
U.S. Pat. No. 4,509,554 discloses a coupling unit for high-pressure and low-pressure uses, with a male coupling part and a female coupling part. Both coupling parts are each equipped with an inner spring-biased valve and an outer spring-biased valve.
SUMMARY DISCLOSURE OF THE INVENTION
It is therefore an object of the invention to create an improved drainage tube device, and in particular a drainage tube device having a coupling unit, which in particular permit a pressure measurement.
This object is achieved in one embodiment by a drainage tube device and a coupling unit according to the invention for removing fluids by suction from a human or animal body comprises:
a coupling unit with first and second coupling parts that can be connected to each other in a leaktight manner,
a first valve that is arranged in the first coupling part, and
a drainage tube with an end that is directed towards the patient, i.e., an end at the patient side, which is held in the second coupling part.
The drainage tube in this embodiment has a multi-lumen design and a drainage conduit and at least one auxiliary conduit. This drainage conduit and at least one of said auxiliary conduits are in fluidic communication with each other at their end directed towards the patient and arranged inside the second coupling part. The drainage tube device further comprises a second valve, which is arranged in the second coupling part and which opens and closes the drainage conduit.
The coupling unit according to the invention for use in a drainage tube device preferably comprises first and second coupling parts that can be connected to each other in a leaktight manner. It also has a first valve that is arranged in the first coupling part. The second coupling part has a recess for securing an end of a multi-lumen drainage tube directed towards the patient. The drainage tube preferably has a drainage conduit and at least one auxiliary conduit, wherein the recess permits fluidic communication between this drainage conduit and at least one of said auxiliary conduits at their end directed towards the patient, and arranged inside the second coupling part. The coupling unit of this embodiment further comprises a second valve, which is arranged in the second coupling part and which opens and closes the drainage conduit.
The foregoing drainage tube device and this coupling unit permit simple connection and separation of the drainage tube to and from other components, in particular another drainage tube, a catheter or a suction head, without clamping being needed. Dripping is avoided by virtue of the valves.
The first valve is preferably always closed in the separated state of the coupling parts, and the second valve is preferably always closed in the absence of an underpressure in the drainage conduit.
If the two coupling parts are connected releasably to each other via a snap-fit connection, this ensures simple connection and separation of the two parts. The two coupling parts can be connected to each other directly. However, they can also be connected to each other indirectly via a bridging part. This bridging part preferably has a first end component and a second end component, wherein the first end component can be connected to the first coupling part and the second end component to the second coupling part in a leaktight manner. The first end component is preferably designed the same as the second coupling part, and the second end component is preferably designed the same as the first coupling part. However, the bridging part preferably does not have any valves itself.
The use of a multi-lumen tube stiffens the drainage conduit and prevents kinking of the conduit. It is advantageous to use several, most preferably exactly three, auxiliary conduits, which are distributed peripherally and in a uniform manner about the centrally arranged drainage conduit.
A hollow space is preferably present in the second coupling part, at that end of the drainage tube directed towards the patient, which hollow space permits the communicating connection between the drainage conduit and the at least one auxiliary conduit. This hollow space permits a pressure measurement, in particular a measurement of the pressure difference between the at least one auxiliary conduit and the drainage conduit. Pressure measurement is therefore possible near the patient, without sensors having to be mounted in the coupling part.
The first valve is preferably a valve which allows or prevents a flow stream in two opposite directions. In a preferred embodiment, the first valve has an elastically deformable piston which is held in the first coupling part and whose deformation takes place upon connection of the first coupling part to the second coupling part or, if it is present, to the bridging part. However, other types of such valves can also be used, for example spring-biased valves.
The second valve can be a one-way valve or a valve which allows or prevents a flow stream in the two opposite directions. It preferably closes only the drainage conduit, not the auxiliary conduit. It is preferably arranged in such a way that, in the closed state of the second valve, there is no communicating connection between the drainage conduit and the at least one auxiliary conduit at that end of the tube directed towards the patient, i.e., the end directed towards the coupling part.
If the second valve is designed as a duckbill valve, it takes up relatively little space, and the coupling unit can be produced relatively inexpensively. A very simple and inexpensive structure is permitted if the second valve is fitted onto that end of the drainage tube directed towards the patient or protrudes at least partially into the drainage conduit. In this way, it can be inserted together with the drainage tube into the coupling part.
The drainage tube is usually adhesively bonded into the coupling part or welded to it. The second valve is preferably held in an interference fit between an abutment of the second coupling part and that end of the drainage tube directed towards the patient.
The coupling unit according to the invention advantageously has a small number of component parts and is therefore simple and inexpensive to produce. It further ensures a relatively high degree of functionality during use.
Other advantageous features are further described in the following detailed description of the invention.